This request is for support, from May 1, 1973 to April 30, 1974, to allow preparation of camera-ready material for publication of a monograph, Chigger Mites of the World: leptotrombidium Complex, of ca. 780 pages (including 240 plates). The research for thissand the related families has been conducted by a team led by Dr. Vercammen-Grandjean for 12 years and is now complete. This generic complex contains those chigger mites that have been confirmed as vectors of scrub typhus to man, and others of epidemiological importance. It is part of series of 13 volumes, of which this will be the second to be published, the only one of major medical, public health, rickettsiological, and epidemiological interest. There already exists partial support for this project from the National Science Foundation. It is expected that the U.S. Army Medical Research & Development Command will support two staff members for this specific project, and that it will be published either by the U.S. Army R & D Command or as a Memoir by the American Entomological Institute. Emergency funds are however requested in case these two agencies do not publish, for publication by imprimateur Hayes, Brussels, Belgium. This work will be the only worldwide, illustrated, fully documented, and complete checklist of this medically important generic complex in the world, and the need for such a monograph is great.